Stop running pub get at gclient sync time and fix build bugs

mojo/public/dart/third_party/barback/lib/src/graph/node_streams.dart

+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library barback.graph.node_streams;
+
+import 'dart:async';
+
+import '../asset/asset_node.dart';
+import '../log.dart';
+import '../utils/stream_pool.dart';
+import 'node_status.dart';
+
+/// A collection of streams that are common to nodes in barback's package graph.
+class NodeStreams {
+  /// A stream that emits an event every time the node's status changes.
+  ///
+  /// This will emit the new status. It's guaranteed to emit an event only when
+  /// the status changes from the previous value. To ensure this, callers should
+  /// emit status changes using [changeStatus]. The initial status is assumed to
+  /// be [NodeStatus.RUNNING].
+  Stream<NodeStatus> get onStatusChange => _onStatusChangeController.stream;
+  final _onStatusChangeController =
+      new StreamController<NodeStatus>.broadcast(sync: true);
+
+  /// A stream that emits any new assets produced by the node.
+  ///
+  /// Assets are emitted synchronously to ensure that any changes are thoroughly
+  /// propagated as soon as they occur.
+  Stream<AssetNode> get onAsset => onAssetPool.stream;
+  final onAssetPool = new StreamPool<AssetNode>.broadcast();
+  final onAssetController =
+      new StreamController<AssetNode>.broadcast(sync: true);
+
+  /// A stream that emits an event whenever any the node logs an entry.
+  Stream<LogEntry> get onLog => onLogPool.stream;
+  final onLogPool = new StreamPool<LogEntry>.broadcast();
+  final onLogController = new StreamController<LogEntry>.broadcast(sync: true);
+
+  var _previousStatus = NodeStatus.RUNNING;
+
+  /// Whether [this] has been closed.
+  bool get isClosed => onAssetController.isClosed;
+
+  NodeStreams() {
+    onAssetPool.add(onAssetController.stream);
+    onLogPool.add(onLogController.stream);
+  }
+
+  /// Emits a status change notification via [onStatusChange].
+  ///
+  /// This guarantees that a change notification won't be emitted if the status
+  /// didn't actually change.
+  void changeStatus(NodeStatus status) {
+    if (_previousStatus != status) _onStatusChangeController.add(status);
+  }
+
+  /// Closes all the streams.
+  void close() {
+    _onStatusChangeController.close();
+    onAssetController.close();
+    onAssetPool.close();
+    onLogController.close();
+    onLogPool.close();
+  }
+}